ObservabilityGramian[ss] gives the observability Gramian of the StateSpaceModel object ss.
PossibleZeroQ[expr] gives True if basic symbolic and numerical methods suggest that expr has value zero, and gives False otherwise.
False
(Built-in Mathematica Symbol) False is the symbol for the Boolean value false.
Algebra`PolynomialContinuedFractions` was available as an add-on package in previous versions of Mathematica and is now available on the web at ...
Algebra`ReIm` was available as an add-on package in previous versions of Mathematica and is now available on the web at library.wolfram.com/infocenter/MathSource/6759.
"How to" Topics Numbers Algebraic Calculations
The built-in function Reduce provides the functionality previously found in Algebra`InequalitySolve`.
All the functionality in Algebra`Quaternions` is available in the newly created Quaternions Package.
And
(Built-in Mathematica Symbol) e_1 && e_2 && ... is the logical AND function. It evaluates its arguments in order, giving False immediately if any of them are False, and True if they are all True.